Causes of death of beavers (Castor fiber) from eastern Germany and observations on parasites, skeletal diseases and tooth anomalies—a long-term analysis

Abstract

The Eurasian beaver, Castor fiber, was nearly extirpated, and in Germany, the relict population at the Middle Elbe, was strictly protected. In the 1930s, the collection and analysis of carcasses of this then-endangered species began in Zerbst, Anhalt, and since 1957 was continued at the Zoological Institute of the University of Halle, Saxony-Anhalt. Records of varying detail from 1282 beavers found dead were recorded up to the year 2009. Here, this unique and valuable dataset is analysed coherently with the focus on the main causes of death separated by age class, sex, month and decade. Traffic accidents have been the major cause of mortality overall since the 1980s, while infections and inflammations have been the main natural cause, with fluctuating frequency during the decades and a peak in the 1950s. With the increased population size and distribution of beavers, routine collection and analysis of cadavers ceased in Halle in 2009. Here, it is argued however that irrespective of the conservation status of beavers, the regular post-mortem surveillance and analysis, of at least regional samples, allows for general health monitoring and provides knowledge about the prevalence of pathogens and parasites and their occurrence, or emergence, and information about contamination with toxins. Additionally, the specimens can contribute to collections for future studies.